Endotracheal intubation is used to mechanically inflate a patient's lungs when the patient is unable to breathe on his or her own. Gases with elevated oxygen concentrations may be introduced through the tube to treat the patient's deoxygenized condition. Notwithstanding its life-giving benefits, intubation also sometimes presents some risk to the patient as an accumulation and pooling of oral secretions laden with microorganisms can seep into the lungs and lead to infection. In some cases, the patient may ultimately be at risk of developing ventilator-acquired or ventilator-assisted pneumonia (VAP).
When a patient is intubated, a balloon cuff on the endotracheal tube located within the trachea inflates to seal the lungs from the outside so that the pressure from the ventilator can be kept in the lungs. VAP is an iatrogenic complication associated with some patients who require ventilation for more than a few days. A major causative mechanism is bacterial contamination of the lung by micro-aspirations of secretions that accumulate over the balloon cuff of an endotracheal or tracheotomy tube. If there is any leak around the cuff, the contaminated secretions can seep into the lungs and cause VAP.
Aspiration of the subglottic secretions has been shown to reduce the incidence of early VAP in intubated, ventilator-assisted patients. Rello, J. et al., Pneumonia in intubated patients: role of respiratory airway care, Am. J. Respir. Crit. Care Med. 154:111 (1996); Valles, J., et al., Continuous aspiration of subglottic secretions in preventing ventilator assisted pneumonia, Ann Intern. Med. 122:179 (1995).
The Hi-Lo Evac® Endotracheal tube with a secondary Evacuation Lumen, manufactured by Mallinckrodt, aims to provide one method for reducing VAP. This dual lumen device allows contaminated secretions to enter an evacuation port near the top of the balloon cuff of the endotracheal tube. The secretions are removed through the evacuation tube, which is connected to wall suction. However, there are several limitations of this device which can sometimes render it ineffective to treat the problem of subglottic secretion pooling with minimal invasion to the patient. The tube may in some circumstances become plugged frequently, reducing its usefulness to the patient unless he or she is reintubated, which is not desirable since intubation should be performed as infrequently as possible as it is considered to be a high-risk procedure. Also, the outside diameter of the Hi-Lo tube is larger than other tubes on the market of the same internal diameter because of its double lumen, which can cause patient discomfort or stress on the vocal cords which have to be pread wider to accommodate this tube. The bulkiness of the Hi-Lo device presents another obstruction to the ease of intubation, removal, and reintubation.
Additionally, a problem with the existing devices with an integral suction channel is that they can also sometimes become plugged with material, requiring replacement of the endotracheal tube, an undesirable action.
All of the references above are incorporated by reference herein, and the description herein of problems and disadvantages of known apparatuses, methods, and devices is not intended to limit the invention to the exclusion of any aspects of these known entities. Indeed, some embodiments of the invention may include aspects of one or more of the known apparatuses, methods, and devices, while at least to some extent, being free from the disadvantages and problems noted herein.